The implementation detail that matters is clear boundaries between planning, execution, validation, and escalation rather than one LLM attempting every responsibility. The decisive point is failure isolation: Option B keeps the agent's decision path observable instead of burying behavior inside one prompt or one service. A workflow is a known path with branches; an agent chooses actions as goals and environment feedback change. That distinction is the core cognition boundary in agentic architecture. The stack-level anchor is clear:
specialized agents can be served, evaluated, and replaced independently when their role or model changes.
The selected option specifically B states "Workflows provide deterministic task sequencing with conditional branching, while agents adapt decisions dynamically based on goals, context, and environment feedback.", which matches the operational requirement rather than a superficial wording match. The rejected options are weaker because single-loop agents and isolated workers collapse planning, memory, and validation into one failure domain, which is brittle under real-time enterprise load. That is the difference between an agent that works in a notebook and an agent that remains reliable in production.